修复封面图 dom bug

src/views/Editor/EditorHeader/index.vue

@@ -374,7 +374,7 @@ const setTemplate = async () =>{
         delete y.TemplateList
       })
     })
-    if(!queryObj.value.CoverImg) {
+    if(queryObj.value.CoverImg=='') {
       datas.loading = false
       mainStore.setToolbarState(ToolbarStates.EL_TEMPLATEDATA)
         return ElMessage({
@@ -384,7 +384,6 @@ const setTemplate = async () =>{
       })
     }
     if(queryObj.value.Title==''||!queryObj.value.LineId||queryObj.value.LineName==''
-    ||queryObj.value.CoverImg==''
     ||queryObj.value.CountryName==''||queryObj.value.SeasonName==''
     ){
       datas.loading = false

src/views/Editor/Toolbar/ElementTemplateData.vue

@@ -129,7 +129,7 @@
 
     <!-- 生成封面图 -->
     <div style="opacity: 0;position: absolute;left: 100px;top: 0;bottom: 0;z-index: -1;" 
-    v-if="model&&slides.length>0">
+    v-if="model&&slides.length>0&&slideIndex>=0">
         <div class="export-img-dialog">
           <div class="thumbnails-view">
             <div class="thumbnails" ref="FeatureImgRef">
@@ -278,6 +278,7 @@
 
     const setDialogForExport = async (type: DialogForExportTypes) => {
         // mainStore.setDialogForExport(type)
+        queryObj.value.CoverImg = ''
         mainMenuVisible.value = false
         isCoverImgStore.setIsCoverImg(true)
         let datas = await exportFeatureImg(FeatureImgRef.value, 'jpeg', 1, false,0)